We report fully printed, disposable supercapacitors with a specific capacitance of up to 25 F g-1 and eco-friendly printed temperature sensors with a temperature coefficient of 450 ppm K-1. We manufactured both devices with a set of functional inks exclusively composed of nanocellulose, carbon particles, non-toxic and biodegradable materials. In particular, we used nanocellulose as rheology modifier, dispersing agent, and binder in inks, and for structural and active components of the devices. With the exponentially growing number of sensors and connected-objects with short service-life brought by the Internet-of-Things era, the development of disposable materials together with sustainable manufacturing techniques is of crucial importance. For instance, the use of metal conductive tracks or epoxy substrates for disposable electronics is a waste of valuable resources and their accumulation in landfills is of environmental concern. In addition to being made of disposable materials only, the supercapacitors and sensors we present in this work are 3D printed. This process enables the monolithic integration of functional components of various geometries, since functional and structural components can be printed in a single procedure. The inks exhibit shear thinning behavior with yield-shear stresses and storage moduli comprised between 102 to 104 MPa and 104 to 106 MPa, respectively. We demonstrate that a minimal feature size of 200 µm is achievable with industry-relevant printing processes. We show that the solvent to binder ratio, solid content and interplay of nanocellulose binders with different carbon particles affect the rheology, the printability, stability and mechanical integrity of the inks, ultimately affecting the performance of the devices.

Nanocellulose inks for disposable and printed electronic devices

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.